Physical change – The type of change in which the physical properties of a material change. It can be changed in shape, state of matter, colour, density, size, odour, solubility, etc. During this change, only the physical traits of the substances are changed.
Chemical change – A substance is said to undergo a chemical change when the chemical properties of a substance alter. As a result, there is either formation or breaking of atomic bonds at the molecular level.
(i) The beating of aluminium metal to make aluminium foil – Physical change
(ii) Digestion of food – Chemical change
(iii) Cutting of a log of wood into pieces – Physical change
(iv) Burning of crackers – Chemical change